1a) rewrite the equation 3sin^2 x+4sinxcosx-4cos^2 x=0 in the form of atan^2 x+btanx+c=0,where a,b and c are integers.
b)hence,solve the equation 3sin^2 x+4sinxcosx-4cos^2 x=0,
where x is between 0 to 360.
pls show clear steps.thx~
F.5 more about equations
2010-09-18 3:26 am
回答 (1)
2010-09-18 3:49 am
✔ 最佳答案
1a)3sin^2 x+4sinxcosx-4cos^2 x=0
(3sin^2 x+4sinxcosx-4cos^2 x)/(cos^2 x)=0
3tan^2 x+4tanx-4=0
1b)
3sin^2 x+4sinxcosx-4cos^2 x=0
3tan^2 x+4tanx-4=0
(3tanx-2)(tanx+2)=0
tanx=2/3 or -2
x=33.7 or 213.7 or 116.6 or 296.6
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